From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 743C44E36F1; Wed, 30 Sep 2026 18:13:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790792011; cv=none; b=PLbEBkp9ESL+kGl6U5msRS+2CXX5UbxQQmjpgi0kraH1s2pp7f404cqdAGedChCFwnFkNTp9etMmj0G96I67YicPOECBaFk9Z7UCDuzZniCdEYjVijDpYjog1bWBHyB1qBNNlKjqgHfOy2NgydH2Akp3v0IlZB9rCFBAPgGLpOE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790792011; c=relaxed/simple; bh=yrbWkvUQYQD5uKvJP9kU7g2pbC8vaEK93KhXlmn0Ico=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WiB83VPmgS3EG44atV3W5+fJyUw9NRj/tZ7o+z0yqYe4NnCvN+jgRoOuWZSlBwZL0MmQYWEWwtz8qXtcRHbT2j95exodISrxwkqGQvmg/kSxSrmU1py6iBQOF6mkU7HAUc8S9Wd6jLexqLWM/eLj+K/zlNc2QLhj5taIlr7T0JM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HJpyqtpb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HJpyqtpb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF94D1F000FF; Wed, 30 Sep 2026 18:13:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790792010; bh=t/m5DvlaLrHFmetrcL0Glee8gGBl1bj2mQZoRdXMQhA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HJpyqtpbHItH+R93CJT8I0e/ek2240wTkhCt+mUgl10LOenISlRjIV5JzrANZZ/z/ 2Hhx/kcGSoKadTAcvUt35YfwIicBLujJJ4y9+XY7NGSGfSjggXbNLNeXvz8ivCAiLo D77v7235pOUUcWqRD8vLptJhyx1hNMl2E7HPhKbk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Hangbin Liu , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 502/752] drop_monitor: synchronize tracepoint unregistration on error path Date: Wed, 30 Sep 2026 17:26:12 +0200 Message-ID: <20260930152409.123842706@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 6a038ef2b57922b6d9ca98ddac0df0681849b704 ] If register_trace_napi_poll() fails in net_dm_trace_on_set(), unregister_trace_kfree_skb() is called to roll back the kfree_skb tracepoint registration. However, tracepoint_synchronize_unregister() is omitted before calling cancel_work_sync() and module_put(). An in-flight probe executing concurrently on another CPU could call schedule_work() after cancel_work_sync() has already returned, leaving a pending work item scheduled after the module reference is dropped. If the module is then unloaded, executing the work item triggers a kernel panic. Add tracepoint_synchronize_unregister() after unregister_trace_kfree_skb() in the error path, matching net_dm_trace_off_set() and net_dm_hw_probe_unregister(). Fixes: 7c747838a558 ("drop_monitor: Split tracing enable / disable to different functions") Signed-off-by: Eric Dumazet Reviewed-by: Hangbin Liu Link: https://patch.msgid.link/20260910204612.3762015-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/drop_monitor.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index ad5d3090f13fe..0449fd8e2936f 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -1153,6 +1153,7 @@ static int net_dm_trace_on_set(struct netlink_ext_ack *extack) err_unregister_trace: unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); + tracepoint_synchronize_unregister(); err_module_put: for_each_possible_cpu(cpu) { struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); -- 2.53.0